As known, the switched reluctance motor rotates a rotor by using a reluctance torque according to a change in the magnetic reluctance and has advantages in that its fabrication cost is low, it does not need much maintenance and has such high reliability that its life span is substantially permanent.
FIG. 1 is a sectional view of the related art switched reluctance motor, and FIG. 2 is a sectional view taken along line II-II in FIG. 1. As shown in the drawings, the switched reluctance motor includes a housing 11, a stator 21 fixed within the housing 11, a rotor 31 rotatably disposed with respect to the stator 21, and a rotor position detecting unit 41 that detects a rotational position of the rotor 31.
A plurality of through holes 13 are formed at side portions of the housing 11 to allow the interior and exterior to communicate with each other, and a stator 21 is fixedly disposed within the housing 11. The rotor 31 is installed to be rotatable centering around a rotational shaft 33 within the stator 21. The rotational shaft 33 is rotatably supported by a bearing 35 fixed at the housing 11.
Meanwhile, the rotor position detecting unit 41 includes a sensor disk 43 integrally and rotatably connected to the rotational shaft 33, and a sensor unit 51 interworks with the sensor disk 43 to detect a rotational position of the rotor 31.
The sensor disk 43 has a disk shape and includes a plurality of protrusions 45 formed to be outwardly protruded in a radial direction at the circumference thereof. A support member 47 is connected at one side of the sensor disk 43 and connected to the rotational shaft 33 to support the sensor disk 43.
The sensor unit 51 includes a plurality of PCBs 53, a PCB fixing member 55 for fixing the PCBs 53 at the housing 11, and a photo-interruptor 57 having a light emitting part 58 and a light receiving part 59 that are disposed to be spaced apart with the protrusions 45 of the sensor disk 43 interposed therebetween in the axial line direction at one side of each PCB 53. Here, the PCBs 53 and the photo-interruptors 57 are provided by the number corresponding to each phase (three-phase) of a coil of the stator 21 and connected at each pre-set position.
The related art switched reluctance motor has the following problems. That is, because the sensor unit 51 is connected in the through holes 13 formed at the lateral portion of the housing 11, the stator 21 needs to be precisely inserted within the housing 11 in consideration of the position of the sensor unit 51 during assembling, so much attention and time are required for the assembling of the stator 21.
In addition, as in case used for a motor of a vacuum cleaner, because the light emitting part 58 and the light receiving part 59 are disposed within the housing 11 in which temperature is relatively high and there is much dust, the life span and sensitivity of the light emitting part 58 and the light receiving part 59 are negatively affected.
In addition, because the sensor disk 43 is connected to the support member 47 by using a screw or the like, time duration for assembling is extended, and the length of the rotational shaft 33 and the size of the housing are increased, thereby being disadvantageous in a compact configuration.